US vaccine giant Merck is discontinuing development of its two experimental Covid-19 vaccines after early trial data showed they failed to generate immune responses comparable to a natural infection or existing vaccines.

The US drug giant, known in Ireland as MSD, has a history of successfully developing vaccines, and had adopted a different strategy from rivals Pfizer, Moderna and Johnson & Johnson, using a more traditional approach of focusing on shots based on weakened viruses.

Merck received interim results from its early-stage trials this month.

Hospital Report

The results were "disappointing, and a bit of a surprise", said Nick Kartsonis, senior vice-president of clinical research for infectious diseases and vaccines at Merck Research Laboratories.

Dutch PM rules out calling in the army after anti-lockdown riots

---

Talks resume between unions and officials over reopening special schools

---

Fifteen junior doctors receive over €100,000 in overtime pay amid Covid-19 pressures

---

Covid-19: NI leaders ‘hopeful’ on North-South travel data sharing plan

---

Both shots generated fewer neutralising antibodies to halt infection than other Covid-19 vaccines, and produced inferior immune responses compared with people who had naturally contracted the coronavirus.

“We didn’t have what we needed to be able to move forward,” Mr Kartsonis said in an interview Sunday.

After evaluating the data, Merck’s senior leadership decided to discontinue the programmes and divert resources to the company’s efforts to develop Covid-19 treatments. – Bloomberg